1. Field of the Invention
The invention may include radio wave antennas to communicate from one station to another. More particularly, the invention may include a surface-mountable microstrip patch antenna having an angled coaxial cable feed for wireless applications.
2. Background Information
An antenna may be that component of a personal communication device, a radio, a television, or a radar system that directs incoming and outgoing radio waves between free space and a transmission line. Antennas are usually metal and have a wide variety of configurations, from the whip or mastlike devices employed for radio and television broadcasting to the large parabolic reflectors used to receive satellite signals and the radio waves generated by distant astronomical objects.
One antenna configuration is known as a microstrip patch antenna. Originally developed in the 1960s for use in aerodynamic military applications, a patch antenna may be viewed as a low-profile antenna that neither disturbs an exterior aerodynamic flow nor excessively protrudes inward to disrupt the internal mechanical structure on which the antenna is supported. A microstrip patch antenna may consist of a rectangular conductor plate or xe2x80x9cpatchxe2x80x9d that is elevated above a ground plane over a dielectric layer. The conductor plate of this planar configuration may be excited from beneath by a probe feed, such as through a round coaxial feed, to generate radio waves. A region of air may serve as the dielectric layer as well as reside above the patch as free space to allow the patch to radiate and receive radio waves.
The ground plane of a patch antenna conventionally is the chassis of the structure to which the antenna is connected. This chassis conventionally is modified so that the coaxial feed may be coupled to the chassis with a connector having a shield. The shield of the connector then is passed from inside the chassis through the connector so that the center conductor of the coaxial cable may make perpendicular contact with the patch from beneath the patch.
The problem with the conventional patch antenna is that its coaxial feed protrudes into the internal area of the mechanical structure on which the patch antenna is supported. This may require additional machining to the supporting structure as well as disrupt the internal area of the mechanical structure. Moreover, the patch antenna connector represents an extra piece whose manufacture and installation expense may represent half of the overall cost of the patch antenna. Further, employing the chassis as the ground plane may limit the applications in which the conventional patch antenna may be installed.